[Magnetic Resonance Imaging Tracing the Biodistribution of SPIO-shRNA Molecular Probe in vivo].

OBJECTIVES: To investigate the biodistribution of superparamagnetic iron oxide (SPIO)-shRNA molecular probe by magnetic resonance imaging (MRI) in vivo. METHODS: Six New Zealand white rabbits were injected intravenously with SPIO-shRNA molecular probe (9.6 mg Fe/kg) via ear edge vein. The blood samples were collected to analyse the pharmacokinetic parameters through measuring the iron content by atomic absorption spectrometry (AAS) method at 30 min before and 1 min, 3 min, 5 min, 10 min, 15 min, 30 min and at 1, 2, 3, 6, 12, and 24 h after the injection. Six Kun Ming (KM) mice were injected intravenously with SPIO-shRNA molecular probe (4.8 mg Fe/kg). The biodistribution of SPIO-shRNA molecular probe was traced by MRI in vivo. Ninety six KM mice were randomly divided into control group and experimental group: each mouse in experimental group was injected intravenously with SPIO-shRNA molecular probe (4.8 mg Fe/kg). The liver, spleen, kidney, brain and muscle of the control group and the experimental group on 1, 3, 5, 7, 9, 11 and 14 d after the injection were collected. The organ iron content were measured by AAS method and Prussian blue staining in order to observe the distribution of the SPIO-shRNA molecular probe in the main organ. RESULTS: Our results demonstrated that the pharmacokinetics of the molecular probe complied with two-compartment model, and the blood half-life was (3.692±0.196) h. The data of MRI showed that the probe were distributed in liver and spleen, and the signs were reduced in accord with the increase of probe's doses in liver and spleen. The probe's metabolism was slow, and the probe was cleared from liver and spleen at 2 weeks after the injection. The results of AAS and Prussian blue staining further testified the results of MRI. CONCLUSIONS: Our data showed the biodistribution of SPIO-shRNA molecular probe in main organs can be traced by MRI in vivo. Meanwhile, it provides important information for the effectiveness of the probe by MRI at tumor in vivo.

Study on Correlation between Expression of CD68 and MRI during the Course of Induced Hepatocellular Carcinoma by Diethylnitrosamine in SD Rats / 实用放射学杂志

Objective To study the pathological foundations of enhanced MRI with superaramagnetic iron oxide(SPIO) and its diagnostic value in liver diseases.Methods 52 SD rats were divided into 2 groups in random,group A(n=40) bred with 2 ‰ diethylnitrosamine(DEN) to induce hepatocellular carcinoma(HCC),group B(n=12) as control group bred with water.6 rats and 2 rats in group A and group B were killed 6,8,11,14,17,20 week later,respectively,before that every SD rats underwent conventional plain and SPIO enhanced MRI examinations.All specimens were examined by HE staining and immunohistochemistry to test CD 68 with SP.Results The successful ratio of induced HCC was 90% and the mortality was 15%.The rats in group A could be divided into 4 stages,including hepatic fibrosis(HF),liver cirrhosis(LC),hyperplastic nodules and hepatocellular carcinoma(HCC).CD 68 positive cell in the normal control tissue(22.83?4.61/HP) was significantly more than that in LC(11.67?4.64/HP)(P